juddering hub motor

[robdon]

[/URL][/IMG] I have a Giant Suede bike that I bought about four months ago, it is in like new condition, up to today it has been running perfect, so I asked my wife to take it for a run as it had not been out for about a month, due to weather.
she had only got to the end of the drive when it started juddering, brought it back as I thought the brakes were sticking ,i released the brakes completely and spun the wheel by hand, still juddering.
It is a front hub motor, anyone have an idea what is wrong, bikes are kept in a dry garage, so no damp.
also checked mudguard was not rubbing

 

[robdon]

[/URL][/IMG] trying to insert photo from photobucket, not working

 

[Deleted member 4366]

Follow the motor wire all the way to the controller and check all the connectors. Is there one under that cover thing on the axle?

 

[EddiePJ]

There you go.

 

[robdon]

THANKS d8veh and EddiePJ.
yes I have checked that one under the guard on the wheel, three large wires,
and six thin they all see ok, large wires on one coupler thin ones on the other.
it still judders even with the battery off, will check at controller end tomorrow
thank you.
eddie how did you get that photo on

 

[EddiePJ]

I hovered the mouse over your black cross, right clicked properties and copied and pasted the details.
Then I deleted everything before the IMG with brackets,then added /IMG with brackets after jpg

 

[robdon]

I have not found any broken wires yet, have now taken chain guards off, and can get at controller under bike, can I test with a multimeter, or test for continuity, are there any guides.
ROB

 

[robdon]

[/URL][/IMG] when I uncouple the phase wires the juddering is no longer there, all the hall wires are ok, at the control end and motor end, the brown phase wire is flat at one side, has been squashed with one of the plastic guard screws, how do I test this piece of wire, it would be quite hard for me to replace, also there is a small black tube coming from the motor it looks like a black wire but is hollow

 

[Deleted member 4366]

Without pictures, it's difficult to understand. Also, what do you mean by juddering? Does it do it when you turn the wheel backwards, forwards or both?

Use this method to post pictures:
http://www.pedelecs.co.uk/forum/threads/does-the-forum-picture-upload-work.15268/

 

[robdon]

photo

 

[robdon]

in am using photo bucket and when I click the photo it says copied,
it judders in both directions, but when I uncoupled the thick phase wires,it stopped

 

[Deleted member 4366]

You shouldn't click the photo. Instead, you should click the "IMG" box in the "Links to share this photo" box on the right hand side.

Does that mean that your motor doesn't have a free-wheel in it. Normally, a geared motor disengages when you spin it forwards, so that it can't judder that way. If you had a direct drive motor, I'd say that the brown wire is partially shorted to one of the other phases. This can happen directly in the wires or indirectly through a faulty MOSFET in the controller. I'm betting on the latter.

 

[robdon]

I will repair the brown wire with a connector, and then see what happens.
can a faulty MOSFET be repaired

 

[Deleted member 4366]

Everything can be repaired, but you should only attempt that if you have experience of fixing PCBs. It's not expensive to replace the whole controller.

 

[robdon]

which one would I require, remember this bike although in lovely condition must be at least 8 years old, I cannot understand how it judders with no battery on bike, ie no power to motor
ROB

 

[Deleted member 4366]

The motor is a generator as well as a motor. If you short any of the phase wires, the generated power stops the motor. If you join all three phase wires, you won't even be able to turn the motor.

Before I could recommend a controller, I'd need to see yours with all the connectors laid out.

 

[robdon]

it is a Sanyo 36 volt, brushless motor in front wheel, 240-380 watts

 

[robdon]

I could not open the controller, but I obtained this photo from elsewhere

 

[robdon]

I have been trying for a couple of hours to do the GRIN TECH test for blown MOSFETS.
On the positive test I get grey wire 1
white wire 1
brown wire 1
this seems to be in order according to GRIN TECH
on the negative test to all three wires the multimeter set on 200 ohms
is all over the place going from 100 as little as 0.4 is this normal
ROB

 

[Deleted member 4366]

Yes, that is normal. All three should behave approximately the same. These testers are pretty good. They short-cut a lot of testing to find out what's wromg:
http://www.ebay.co.uk/itm/24V-60V-E-bike-Motor-Controller-Tester-Car-Quick-Electro-Scooter-Brushless-1PC-/131029644494?pt=UK_Motorcycle_Parts&hash=item1e81f9b4ce

Your controller is a bit special for your bike. Alternatives are available, but you might have to be a bit creative in how/where to fix one.